The likelihood one rogue shark is responsible for two attacks in less than 24 hours in Queensland's Whitsunday Islands is nearly nil, shark experts say.
When Mr Macdonald arrived, he worked with doctor from a nearby boat who had come to help, as well as the woman's family who had been on the yacht.
She was then airlifted to Mackay hospital by rescue helicopter where she remains in a critical condition.
Experts have said shark attacks have become all the more common due to waterspouts activities being on the increase.
A RACQ CQ Rescue spokeswoman confirmed their chopper had been involved in a winch operation off a vessel at Sawmill Bay at Whitsunday Island, not Lindeman as was initially reported.
QAS Rockhampton operations centre manager Mindy Thomas said the girl was in a critical but stable condition with a significant leg injury.
The 12-year-old girl, a tourist from New Zealand, had been in the water near Cid Harbour when she was bitten about 1.45pm, prompting the deployment of the RACQ CQ Rescue helicopter.
The injured woman and two others had to be put into a dinghy and repositioned about 100 metres from the yacht because it lacked an open deck.
Mr Macdonald contacted the RACQ CQ Rescue helicopter on the radio to co-ordinate what needed to be done for her to be picked up from the boat.
Tracey Eastwick, from the Queensland Ambulance Service, said the girl, who was in the water with her father and sister, was bitten just below the groin and suffered significant blood loss from large wounds on her thigh. Of these, two people died.
Family Based Care chief executive Doug Doherty said Ms Barwick and Craig were regular visitors to the popular tourist destination in the heart of the Great Barrier Reef.
On Friday, a Queensland Shark Control Program contractor will deploy three shark control drumlines - a system of buoys "designed to remove larger, unsafe sharks from an area", according to the Fisheries spokesman.
The department's shark control program manager Jeff Krause said it was too early to determine what species of shark was responsible for the first attacks in the area in eight years.
The crew was doing a beacon search in the vicinity of the Bowen area when they were called to the shark attack incident.
She had been pulled out of the water by others on the 36-foot yacht she had been swimming from.
"(But) it is effective in reducing the overall number of sharks in the area, making it a safer place to swim.